Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;

import static java.lang.Math.abs;
import static java.lang.Math.max;
import static java.lang.Math.min;


public class Main {


    public static void main(String [] args){
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Integer readFromFile=new Integer(1);
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskD solver = new TaskD();
        solver.solve(1, in, out);
        out.close();
    }
    static class TaskD {
        int maxInt = Integer.MAX_VALUE;

        void print(PrintWriter out, List<int[]> row, List<int[]> column) {
            for (int i = 0; i < row.size(); i++) {
                for (int j = 0; j < row.get(i)[1]; j++) {
                    out.println("row " + row.get(i)[0]);
                }
            }
            for (int i = 0; i < column.size(); i++) {
                for (int j = 0; j < column.get(i)[1]; j++) {
                    out.println("col " + column.get(i)[0]);
                }
            }
        }
        void toMax(int [] array){
            for(int i=0; i<array.length; i++) {
                array[i] = maxInt;
            }
        }
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            int A[][] = new int[n][m];
            int[] minRow = new int[n];
            int[] minColumn = new int[m];
            int answer = 0;
            int answer2 = 0;
            List<int[]> listR = new ArrayList<>(100);
            List<int[]> listC = new ArrayList<>(100);
            List<int[]> listR_2 = new ArrayList<>(100);
            List<int[]> listC_2 = new ArrayList<>(100);
            toMax(minRow);
            toMax(minColumn);
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    A[i][j] = in.nextInt();
                    if (A[i][j] < minRow[i]) {
                        minRow[i] = A[i][j];
                    }
                    minColumn[j] = min(minColumn[j], A[i][j]);
                }
                answer += minRow[i];
                listR.add(new int[]{i + 1, minRow[i]});
            }
            for(int j=0; j<m; j++){
                answer2 += minColumn[j];
                listC_2.add(new int[]{j + 1, minColumn[j]});
            }

            for (int j = 0; j < m; j++) {
                int difrent = A[0][j] - minRow[0];
                for (int i = 1; i < n; i++) {
                    if (abs(A[i][j] - minRow[i]) != difrent) {
                        out.println(-1);
                        return;
                    }
                }
                answer += difrent;
                listC.add(new int[]{j + 1, difrent});
            }
            for (int i = 0; i < n; i++) {
                int result = A[i][0]-minColumn[0];
                if(result!=0){
                    answer2+=result;
                    listR_2.add(new int[]{i + 1, result});
                }
            }
            if (answer <= answer2) {
                out.println(answer);
                print(out, listR, listC);
            }else{
                out.println(answer2);
                print(out, listR_2, listC_2);
            }

        }
    }
    class Pair{
        int first;
        int second;
        Pair(int first, int second){
            this.first = first;
            this.second = second;
        }
    }
    void madAdd(Map <Character, Integer> map, char value){
        if(map.containsKey(value)){
            map.put(value, map.get(value)+1);
        }else{
            map.put(value, 1);
        }
    }
    static class InputReader {
        BufferedReader br;
        StringTokenizer st;
        String st1;
        File file = new File("text.txt");
        public InputReader(InputStream in) {
            br = new BufferedReader(new InputStreamReader(in));
            st = null;
        }
        public InputReader(int i) {
            try {
                br  = new BufferedReader(
                        new InputStreamReader(new FileInputStream(file)));
            } catch (FileNotFoundException e1) {
                System.out.println("File is not find");
            }
            st = null;
        }
        public String next(){
            while (st==null || !st.hasMoreTokens()){
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return st.nextToken();
        }
        public String nextLine(){
            try {
                st1 = new String(br.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
            return st1;
        }
        public int nextInt()  {return Integer.parseInt(next());}
        public long nextLong(){
            return Long.parseLong(next());
        }
        public Double nextDouble(){
            return Double.parseDouble(next());
        }
        public Byte nextByte() {
            return Byte.parseByte(next());
        }
        private int idx;
        public Character nextChar() {
            if(st1==null) {
                st1 = next();
                idx = 0;
            }
            if(idx!=(st1.length())-1){
                return st1.charAt(idx++);
            }else{
                char  c= st1.charAt(idx);
                st1 = null;
                return c;
            }
        }
        public void newFile() {
            try {
                FileWriter write = new FileWriter(file);
                write.write("something for cheaking");
                write.close();

            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        public void writeFile1(){
            try{
                FileWriter write = new FileWriter(file);
                write.append("100000"+" ");
                for(int i=0; i<100000; i++){
                    write.append(new Integer((int)(Math.random()*5000)).toString()+" ");
                }
                write.close();

            }catch(IOException e){
                e.printStackTrace();
            }
        }
    }
}